[jklingel]

Is it not true that the vent pipe coming from a kitchen sink DWV needs to rise 6" before it runs horizontally? ("Horizontally" meaning w/ 1/8" per foot slope back to the drain.) I seem to recall being jazzed on that on my last sink, but the options were few with a low window over the sink. So, is the 6" rule correct, or does the rule get slurred over because of windows in the way? Also, in dry vent lines, it seems I see sanitary tees oriented both up and down, down being like they need to be in the drain lines. Is there a proper sweep direction for san tees in the vent line, or, as I heard here once, it does not matter because "air does not care"? Thanks. I only do this every few years and just don't have the details glued into my head. (And I've tried various glues, too....) john

 

[Ghostmaker]

The vent for any sink must rise 6 inches above the flood level rim of the sink prior to going horizontal. The flood level rim is the point that if the drain is blocked the water will exit the sink and hit the floor. That is why if a window is the problem you run the vent to the left or right of the sink window and drill the drain under the window use a san tee in the vertical position when connecting to the vent.

The tees in a vent do not care but a vent always must be self draining good practice is the tees are installed to facilitate this draining.

 

[jklingel]

Ghost: Thank you for the reply. I just measured the sink I referred to above, and there are 8 inches between the top of the sink's flood level rim and the bottom of the window sill. Thus, I DID have enough room to comply, barely, but must have spaced it out and run horizontally too soon. Henceforth, I will rise before I run. On the san tees, what you said is what has always made sense to me. I don't build houses often and will make sure I get this right this time. cheers. john